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1/*
2 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
3 * Licensed under the GPL
4 */
5
6#include <linux/clockchips.h>
7#include <linux/init.h>
8#include <linux/interrupt.h>
9#include <linux/jiffies.h>
10#include <linux/threads.h>
11#include <asm/irq.h>
12#include <asm/param.h>
13#include "kern_util.h"
14#include "os.h"
15
16void timer_handler(int sig, struct uml_pt_regs *regs)
17{
18 unsigned long flags;
19
20 local_irq_save(flags);
21 do_IRQ(TIMER_IRQ, regs);
22 local_irq_restore(flags);
23}
24
25static void itimer_set_mode(enum clock_event_mode mode,
26 struct clock_event_device *evt)
27{
28 switch (mode) {
29 case CLOCK_EVT_MODE_PERIODIC:
30 set_interval();
31 break;
32
33 case CLOCK_EVT_MODE_SHUTDOWN:
34 case CLOCK_EVT_MODE_UNUSED:
35 case CLOCK_EVT_MODE_ONESHOT:
36 disable_timer();
37 break;
38
39 case CLOCK_EVT_MODE_RESUME:
40 break;
41 }
42}
43
44static int itimer_next_event(unsigned long delta,
45 struct clock_event_device *evt)
46{
47 return timer_one_shot(delta + 1);
48}
49
50static struct clock_event_device itimer_clockevent = {
51 .name = "itimer",
52 .rating = 250,
53 .cpumask = cpu_all_mask,
54 .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
55 .set_mode = itimer_set_mode,
56 .set_next_event = itimer_next_event,
57 .shift = 32,
58 .irq = 0,
59};
60
61static irqreturn_t um_timer(int irq, void *dev)
62{
63 (*itimer_clockevent.event_handler)(&itimer_clockevent);
64
65 return IRQ_HANDLED;
66}
67
68static cycle_t itimer_read(struct clocksource *cs)
69{
70 return os_nsecs() / 1000;
71}
72
73static struct clocksource itimer_clocksource = {
74 .name = "itimer",
75 .rating = 300,
76 .read = itimer_read,
77 .mask = CLOCKSOURCE_MASK(64),
78 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
79};
80
81static void __init setup_itimer(void)
82{
83 int err;
84
85 err = request_irq(TIMER_IRQ, um_timer, 0, "timer", NULL);
86 if (err != 0)
87 printk(KERN_ERR "register_timer : request_irq failed - "
88 "errno = %d\n", -err);
89
90 itimer_clockevent.mult = div_sc(HZ, NSEC_PER_SEC, 32);
91 itimer_clockevent.max_delta_ns =
92 clockevent_delta2ns(60 * HZ, &itimer_clockevent);
93 itimer_clockevent.min_delta_ns =
94 clockevent_delta2ns(1, &itimer_clockevent);
95 err = clocksource_register_hz(&itimer_clocksource, USEC_PER_SEC);
96 if (err) {
97 printk(KERN_ERR "clocksource_register_hz returned %d\n", err);
98 return;
99 }
100 clockevents_register_device(&itimer_clockevent);
101}
102
103void read_persistent_clock(struct timespec *ts)
104{
105 long long nsecs = os_nsecs();
106
107 set_normalized_timespec(ts, nsecs / NSEC_PER_SEC,
108 nsecs % NSEC_PER_SEC);
109}
110
111void __init time_init(void)
112{
113 timer_init();
114 late_time_init = setup_itimer;
115}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2015 Anton Ivanov (aivanov@{brocade.com,kot-begemot.co.uk})
4 * Copyright (C) 2015 Thomas Meyer (thomas@m3y3r.de)
5 * Copyright (C) 2012-2014 Cisco Systems
6 * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
7 * Copyright (C) 2019 Intel Corporation
8 */
9
10#include <linux/clockchips.h>
11#include <linux/init.h>
12#include <linux/interrupt.h>
13#include <linux/jiffies.h>
14#include <linux/mm.h>
15#include <linux/sched.h>
16#include <linux/spinlock.h>
17#include <linux/threads.h>
18#include <asm/irq.h>
19#include <asm/param.h>
20#include <kern_util.h>
21#include <os.h>
22#include <linux/time-internal.h>
23#include <linux/um_timetravel.h>
24#include <shared/init.h>
25
26#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
27enum time_travel_mode time_travel_mode;
28EXPORT_SYMBOL_GPL(time_travel_mode);
29
30static bool time_travel_start_set;
31static unsigned long long time_travel_start;
32static unsigned long long time_travel_time;
33static LIST_HEAD(time_travel_events);
34static LIST_HEAD(time_travel_irqs);
35static unsigned long long time_travel_timer_interval;
36static unsigned long long time_travel_next_event;
37static struct time_travel_event time_travel_timer_event;
38static int time_travel_ext_fd = -1;
39static unsigned int time_travel_ext_waiting;
40static bool time_travel_ext_prev_request_valid;
41static unsigned long long time_travel_ext_prev_request;
42static bool time_travel_ext_free_until_valid;
43static unsigned long long time_travel_ext_free_until;
44
45static void time_travel_set_time(unsigned long long ns)
46{
47 if (unlikely(ns < time_travel_time))
48 panic("time-travel: time goes backwards %lld -> %lld\n",
49 time_travel_time, ns);
50 else if (unlikely(ns >= S64_MAX))
51 panic("The system was going to sleep forever, aborting");
52
53 time_travel_time = ns;
54}
55
56enum time_travel_message_handling {
57 TTMH_IDLE,
58 TTMH_POLL,
59 TTMH_READ,
60};
61
62static void time_travel_handle_message(struct um_timetravel_msg *msg,
63 enum time_travel_message_handling mode)
64{
65 struct um_timetravel_msg resp = {
66 .op = UM_TIMETRAVEL_ACK,
67 };
68 int ret;
69
70 /*
71 * We can't unlock here, but interrupt signals with a timetravel_handler
72 * (see um_request_irq_tt) get to the timetravel_handler anyway.
73 */
74 if (mode != TTMH_READ) {
75 BUG_ON(mode == TTMH_IDLE && !irqs_disabled());
76
77 while (os_poll(1, &time_travel_ext_fd) != 0) {
78 /* nothing */
79 }
80 }
81
82 ret = os_read_file(time_travel_ext_fd, msg, sizeof(*msg));
83
84 if (ret == 0)
85 panic("time-travel external link is broken\n");
86 if (ret != sizeof(*msg))
87 panic("invalid time-travel message - %d bytes\n", ret);
88
89 switch (msg->op) {
90 default:
91 WARN_ONCE(1, "time-travel: unexpected message %lld\n",
92 (unsigned long long)msg->op);
93 break;
94 case UM_TIMETRAVEL_ACK:
95 return;
96 case UM_TIMETRAVEL_RUN:
97 time_travel_set_time(msg->time);
98 break;
99 case UM_TIMETRAVEL_FREE_UNTIL:
100 time_travel_ext_free_until_valid = true;
101 time_travel_ext_free_until = msg->time;
102 break;
103 }
104
105 resp.seq = msg->seq;
106 os_write_file(time_travel_ext_fd, &resp, sizeof(resp));
107}
108
109static u64 time_travel_ext_req(u32 op, u64 time)
110{
111 static int seq;
112 int mseq = ++seq;
113 struct um_timetravel_msg msg = {
114 .op = op,
115 .time = time,
116 .seq = mseq,
117 };
118
119 /*
120 * We need to block even the timetravel handlers of SIGIO here and
121 * only restore their use when we got the ACK - otherwise we may
122 * (will) get interrupted by that, try to queue the IRQ for future
123 * processing and thus send another request while we're still waiting
124 * for an ACK, but the peer doesn't know we got interrupted and will
125 * send the ACKs in the same order as the message, but we'd need to
126 * see them in the opposite order ...
127 *
128 * This wouldn't matter *too* much, but some ACKs carry the
129 * current time (for UM_TIMETRAVEL_GET) and getting another
130 * ACK without a time would confuse us a lot!
131 *
132 * The sequence number assignment that happens here lets us
133 * debug such message handling issues more easily.
134 */
135 block_signals_hard();
136 os_write_file(time_travel_ext_fd, &msg, sizeof(msg));
137
138 while (msg.op != UM_TIMETRAVEL_ACK)
139 time_travel_handle_message(&msg, TTMH_READ);
140
141 if (msg.seq != mseq)
142 panic("time-travel: ACK message has different seqno! op=%d, seq=%d != %d time=%lld\n",
143 msg.op, msg.seq, mseq, msg.time);
144
145 if (op == UM_TIMETRAVEL_GET)
146 time_travel_set_time(msg.time);
147 unblock_signals_hard();
148
149 return msg.time;
150}
151
152void __time_travel_wait_readable(int fd)
153{
154 int fds[2] = { fd, time_travel_ext_fd };
155 int ret;
156
157 if (time_travel_mode != TT_MODE_EXTERNAL)
158 return;
159
160 while ((ret = os_poll(2, fds))) {
161 struct um_timetravel_msg msg;
162
163 if (ret == 1)
164 time_travel_handle_message(&msg, TTMH_READ);
165 }
166}
167EXPORT_SYMBOL_GPL(__time_travel_wait_readable);
168
169static void time_travel_ext_update_request(unsigned long long time)
170{
171 if (time_travel_mode != TT_MODE_EXTERNAL)
172 return;
173
174 /* asked for exactly this time previously */
175 if (time_travel_ext_prev_request_valid &&
176 time == time_travel_ext_prev_request)
177 return;
178
179 /*
180 * if we're running and are allowed to run past the request
181 * then we don't need to update it either
182 */
183 if (!time_travel_ext_waiting && time_travel_ext_free_until_valid &&
184 time < time_travel_ext_free_until)
185 return;
186
187 time_travel_ext_prev_request = time;
188 time_travel_ext_prev_request_valid = true;
189 time_travel_ext_req(UM_TIMETRAVEL_REQUEST, time);
190}
191
192void __time_travel_propagate_time(void)
193{
194 static unsigned long long last_propagated;
195
196 if (last_propagated == time_travel_time)
197 return;
198
199 time_travel_ext_req(UM_TIMETRAVEL_UPDATE, time_travel_time);
200 last_propagated = time_travel_time;
201}
202EXPORT_SYMBOL_GPL(__time_travel_propagate_time);
203
204/* returns true if we must do a wait to the simtime device */
205static bool time_travel_ext_request(unsigned long long time)
206{
207 /*
208 * If we received an external sync point ("free until") then we
209 * don't have to request/wait for anything until then, unless
210 * we're already waiting.
211 */
212 if (!time_travel_ext_waiting && time_travel_ext_free_until_valid &&
213 time < time_travel_ext_free_until)
214 return false;
215
216 time_travel_ext_update_request(time);
217 return true;
218}
219
220static void time_travel_ext_wait(bool idle)
221{
222 struct um_timetravel_msg msg = {
223 .op = UM_TIMETRAVEL_ACK,
224 };
225
226 time_travel_ext_prev_request_valid = false;
227 time_travel_ext_free_until_valid = false;
228 time_travel_ext_waiting++;
229
230 time_travel_ext_req(UM_TIMETRAVEL_WAIT, -1);
231
232 /*
233 * Here we are deep in the idle loop, so we have to break out of the
234 * kernel abstraction in a sense and implement this in terms of the
235 * UML system waiting on the VQ interrupt while sleeping, when we get
236 * the signal it'll call time_travel_ext_vq_notify_done() completing the
237 * call.
238 */
239 while (msg.op != UM_TIMETRAVEL_RUN)
240 time_travel_handle_message(&msg, idle ? TTMH_IDLE : TTMH_POLL);
241
242 time_travel_ext_waiting--;
243
244 /* we might request more stuff while polling - reset when we run */
245 time_travel_ext_prev_request_valid = false;
246}
247
248static void time_travel_ext_get_time(void)
249{
250 time_travel_ext_req(UM_TIMETRAVEL_GET, -1);
251}
252
253static void __time_travel_update_time(unsigned long long ns, bool idle)
254{
255 if (time_travel_mode == TT_MODE_EXTERNAL && time_travel_ext_request(ns))
256 time_travel_ext_wait(idle);
257 else
258 time_travel_set_time(ns);
259}
260
261static struct time_travel_event *time_travel_first_event(void)
262{
263 return list_first_entry_or_null(&time_travel_events,
264 struct time_travel_event,
265 list);
266}
267
268static void __time_travel_add_event(struct time_travel_event *e,
269 unsigned long long time)
270{
271 struct time_travel_event *tmp;
272 bool inserted = false;
273 unsigned long flags;
274
275 if (e->pending)
276 return;
277
278 e->pending = true;
279 e->time = time;
280
281 local_irq_save(flags);
282 list_for_each_entry(tmp, &time_travel_events, list) {
283 /*
284 * Add the new entry before one with higher time,
285 * or if they're equal and both on stack, because
286 * in that case we need to unwind the stack in the
287 * right order, and the later event (timer sleep
288 * or such) must be dequeued first.
289 */
290 if ((tmp->time > e->time) ||
291 (tmp->time == e->time && tmp->onstack && e->onstack)) {
292 list_add_tail(&e->list, &tmp->list);
293 inserted = true;
294 break;
295 }
296 }
297
298 if (!inserted)
299 list_add_tail(&e->list, &time_travel_events);
300
301 tmp = time_travel_first_event();
302 time_travel_ext_update_request(tmp->time);
303 time_travel_next_event = tmp->time;
304 local_irq_restore(flags);
305}
306
307static void time_travel_add_event(struct time_travel_event *e,
308 unsigned long long time)
309{
310 if (WARN_ON(!e->fn))
311 return;
312
313 __time_travel_add_event(e, time);
314}
315
316void time_travel_add_event_rel(struct time_travel_event *e,
317 unsigned long long delay_ns)
318{
319 time_travel_add_event(e, time_travel_time + delay_ns);
320}
321
322void time_travel_periodic_timer(struct time_travel_event *e)
323{
324 time_travel_add_event(&time_travel_timer_event,
325 time_travel_time + time_travel_timer_interval);
326 deliver_alarm();
327}
328
329void deliver_time_travel_irqs(void)
330{
331 struct time_travel_event *e;
332 unsigned long flags;
333
334 /*
335 * Don't do anything for most cases. Note that because here we have
336 * to disable IRQs (and re-enable later) we'll actually recurse at
337 * the end of the function, so this is strictly necessary.
338 */
339 if (likely(list_empty(&time_travel_irqs)))
340 return;
341
342 local_irq_save(flags);
343 irq_enter();
344 while ((e = list_first_entry_or_null(&time_travel_irqs,
345 struct time_travel_event,
346 list))) {
347 list_del(&e->list);
348 e->pending = false;
349 e->fn(e);
350 }
351 irq_exit();
352 local_irq_restore(flags);
353}
354
355static void time_travel_deliver_event(struct time_travel_event *e)
356{
357 if (e == &time_travel_timer_event) {
358 /*
359 * deliver_alarm() does the irq_enter/irq_exit
360 * by itself, so must handle it specially here
361 */
362 e->fn(e);
363 } else if (irqs_disabled()) {
364 list_add_tail(&e->list, &time_travel_irqs);
365 /*
366 * set pending again, it was set to false when the
367 * event was deleted from the original list, but
368 * now it's still pending until we deliver the IRQ.
369 */
370 e->pending = true;
371 } else {
372 unsigned long flags;
373
374 local_irq_save(flags);
375 irq_enter();
376 e->fn(e);
377 irq_exit();
378 local_irq_restore(flags);
379 }
380}
381
382bool time_travel_del_event(struct time_travel_event *e)
383{
384 unsigned long flags;
385
386 if (!e->pending)
387 return false;
388 local_irq_save(flags);
389 list_del(&e->list);
390 e->pending = false;
391 local_irq_restore(flags);
392 return true;
393}
394
395static void time_travel_update_time(unsigned long long next, bool idle)
396{
397 struct time_travel_event ne = {
398 .onstack = true,
399 };
400 struct time_travel_event *e;
401 bool finished = idle;
402
403 /* add it without a handler - we deal with that specifically below */
404 __time_travel_add_event(&ne, next);
405
406 do {
407 e = time_travel_first_event();
408
409 BUG_ON(!e);
410 __time_travel_update_time(e->time, idle);
411
412 /* new events may have been inserted while we were waiting */
413 if (e == time_travel_first_event()) {
414 BUG_ON(!time_travel_del_event(e));
415 BUG_ON(time_travel_time != e->time);
416
417 if (e == &ne) {
418 finished = true;
419 } else {
420 if (e->onstack)
421 panic("On-stack event dequeued outside of the stack! time=%lld, event time=%lld, event=%pS\n",
422 time_travel_time, e->time, e);
423 time_travel_deliver_event(e);
424 }
425 }
426
427 e = time_travel_first_event();
428 if (e)
429 time_travel_ext_update_request(e->time);
430 } while (ne.pending && !finished);
431
432 time_travel_del_event(&ne);
433}
434
435static void time_travel_update_time_rel(unsigned long long offs)
436{
437 unsigned long flags;
438
439 /*
440 * Disable interrupts before calculating the new time so
441 * that a real timer interrupt (signal) can't happen at
442 * a bad time e.g. after we read time_travel_time but
443 * before we've completed updating the time.
444 */
445 local_irq_save(flags);
446 time_travel_update_time(time_travel_time + offs, false);
447 local_irq_restore(flags);
448}
449
450void time_travel_ndelay(unsigned long nsec)
451{
452 /*
453 * Not strictly needed to use _rel() version since this is
454 * only used in INFCPU/EXT modes, but it doesn't hurt and
455 * is more readable too.
456 */
457 time_travel_update_time_rel(nsec);
458}
459EXPORT_SYMBOL(time_travel_ndelay);
460
461void time_travel_add_irq_event(struct time_travel_event *e)
462{
463 BUG_ON(time_travel_mode != TT_MODE_EXTERNAL);
464
465 time_travel_ext_get_time();
466 /*
467 * We could model interrupt latency here, for now just
468 * don't have any latency at all and request the exact
469 * same time (again) to run the interrupt...
470 */
471 time_travel_add_event(e, time_travel_time);
472}
473EXPORT_SYMBOL_GPL(time_travel_add_irq_event);
474
475static void time_travel_oneshot_timer(struct time_travel_event *e)
476{
477 deliver_alarm();
478}
479
480void time_travel_sleep(void)
481{
482 /*
483 * Wait "forever" (using S64_MAX because there are some potential
484 * wrapping issues, especially with the current TT_MODE_EXTERNAL
485 * controller application.
486 */
487 unsigned long long next = S64_MAX;
488
489 if (time_travel_mode == TT_MODE_BASIC)
490 os_timer_disable();
491
492 time_travel_update_time(next, true);
493
494 if (time_travel_mode == TT_MODE_BASIC &&
495 time_travel_timer_event.pending) {
496 if (time_travel_timer_event.fn == time_travel_periodic_timer) {
497 /*
498 * This is somewhat wrong - we should get the first
499 * one sooner like the os_timer_one_shot() below...
500 */
501 os_timer_set_interval(time_travel_timer_interval);
502 } else {
503 os_timer_one_shot(time_travel_timer_event.time - next);
504 }
505 }
506}
507
508static void time_travel_handle_real_alarm(void)
509{
510 time_travel_set_time(time_travel_next_event);
511
512 time_travel_del_event(&time_travel_timer_event);
513
514 if (time_travel_timer_event.fn == time_travel_periodic_timer)
515 time_travel_add_event(&time_travel_timer_event,
516 time_travel_time +
517 time_travel_timer_interval);
518}
519
520static void time_travel_set_interval(unsigned long long interval)
521{
522 time_travel_timer_interval = interval;
523}
524
525static int time_travel_connect_external(const char *socket)
526{
527 const char *sep;
528 unsigned long long id = (unsigned long long)-1;
529 int rc;
530
531 if ((sep = strchr(socket, ':'))) {
532 char buf[25] = {};
533 if (sep - socket > sizeof(buf) - 1)
534 goto invalid_number;
535
536 memcpy(buf, socket, sep - socket);
537 if (kstrtoull(buf, 0, &id)) {
538invalid_number:
539 panic("time-travel: invalid external ID in string '%s'\n",
540 socket);
541 return -EINVAL;
542 }
543
544 socket = sep + 1;
545 }
546
547 rc = os_connect_socket(socket);
548 if (rc < 0) {
549 panic("time-travel: failed to connect to external socket %s\n",
550 socket);
551 return rc;
552 }
553
554 time_travel_ext_fd = rc;
555
556 time_travel_ext_req(UM_TIMETRAVEL_START, id);
557
558 return 1;
559}
560
561static void time_travel_set_start(void)
562{
563 if (time_travel_start_set)
564 return;
565
566 switch (time_travel_mode) {
567 case TT_MODE_EXTERNAL:
568 time_travel_start = time_travel_ext_req(UM_TIMETRAVEL_GET_TOD, -1);
569 /* controller gave us the *current* time, so adjust by that */
570 time_travel_ext_get_time();
571 time_travel_start -= time_travel_time;
572 break;
573 case TT_MODE_INFCPU:
574 case TT_MODE_BASIC:
575 if (!time_travel_start_set)
576 time_travel_start = os_persistent_clock_emulation();
577 break;
578 case TT_MODE_OFF:
579 /* we just read the host clock with os_persistent_clock_emulation() */
580 break;
581 }
582
583 time_travel_start_set = true;
584}
585#else /* CONFIG_UML_TIME_TRAVEL_SUPPORT */
586#define time_travel_start_set 0
587#define time_travel_start 0
588#define time_travel_time 0
589#define time_travel_ext_waiting 0
590
591static inline void time_travel_update_time(unsigned long long ns, bool idle)
592{
593}
594
595static inline void time_travel_update_time_rel(unsigned long long offs)
596{
597}
598
599static inline void time_travel_handle_real_alarm(void)
600{
601}
602
603static void time_travel_set_interval(unsigned long long interval)
604{
605}
606
607static inline void time_travel_set_start(void)
608{
609}
610
611/* fail link if this actually gets used */
612extern u64 time_travel_ext_req(u32 op, u64 time);
613
614/* these are empty macros so the struct/fn need not exist */
615#define time_travel_add_event(e, time) do { } while (0)
616/* externally not usable - redefine here so we can */
617#undef time_travel_del_event
618#define time_travel_del_event(e) do { } while (0)
619#endif
620
621void timer_handler(int sig, struct siginfo *unused_si, struct uml_pt_regs *regs)
622{
623 unsigned long flags;
624
625 /*
626 * In basic time-travel mode we still get real interrupts
627 * (signals) but since we don't read time from the OS, we
628 * must update the simulated time here to the expiry when
629 * we get a signal.
630 * This is not the case in inf-cpu mode, since there we
631 * never get any real signals from the OS.
632 */
633 if (time_travel_mode == TT_MODE_BASIC)
634 time_travel_handle_real_alarm();
635
636 local_irq_save(flags);
637 do_IRQ(TIMER_IRQ, regs);
638 local_irq_restore(flags);
639}
640
641static int itimer_shutdown(struct clock_event_device *evt)
642{
643 if (time_travel_mode != TT_MODE_OFF)
644 time_travel_del_event(&time_travel_timer_event);
645
646 if (time_travel_mode != TT_MODE_INFCPU &&
647 time_travel_mode != TT_MODE_EXTERNAL)
648 os_timer_disable();
649
650 return 0;
651}
652
653static int itimer_set_periodic(struct clock_event_device *evt)
654{
655 unsigned long long interval = NSEC_PER_SEC / HZ;
656
657 if (time_travel_mode != TT_MODE_OFF) {
658 time_travel_del_event(&time_travel_timer_event);
659 time_travel_set_event_fn(&time_travel_timer_event,
660 time_travel_periodic_timer);
661 time_travel_set_interval(interval);
662 time_travel_add_event(&time_travel_timer_event,
663 time_travel_time + interval);
664 }
665
666 if (time_travel_mode != TT_MODE_INFCPU &&
667 time_travel_mode != TT_MODE_EXTERNAL)
668 os_timer_set_interval(interval);
669
670 return 0;
671}
672
673static int itimer_next_event(unsigned long delta,
674 struct clock_event_device *evt)
675{
676 delta += 1;
677
678 if (time_travel_mode != TT_MODE_OFF) {
679 time_travel_del_event(&time_travel_timer_event);
680 time_travel_set_event_fn(&time_travel_timer_event,
681 time_travel_oneshot_timer);
682 time_travel_add_event(&time_travel_timer_event,
683 time_travel_time + delta);
684 }
685
686 if (time_travel_mode != TT_MODE_INFCPU &&
687 time_travel_mode != TT_MODE_EXTERNAL)
688 return os_timer_one_shot(delta);
689
690 return 0;
691}
692
693static int itimer_one_shot(struct clock_event_device *evt)
694{
695 return itimer_next_event(0, evt);
696}
697
698static struct clock_event_device timer_clockevent = {
699 .name = "posix-timer",
700 .rating = 250,
701 .cpumask = cpu_possible_mask,
702 .features = CLOCK_EVT_FEAT_PERIODIC |
703 CLOCK_EVT_FEAT_ONESHOT,
704 .set_state_shutdown = itimer_shutdown,
705 .set_state_periodic = itimer_set_periodic,
706 .set_state_oneshot = itimer_one_shot,
707 .set_next_event = itimer_next_event,
708 .shift = 0,
709 .max_delta_ns = 0xffffffff,
710 .max_delta_ticks = 0xffffffff,
711 .min_delta_ns = TIMER_MIN_DELTA,
712 .min_delta_ticks = TIMER_MIN_DELTA, // microsecond resolution should be enough for anyone, same as 640K RAM
713 .irq = 0,
714 .mult = 1,
715};
716
717static irqreturn_t um_timer(int irq, void *dev)
718{
719 if (get_current()->mm != NULL)
720 {
721 /* userspace - relay signal, results in correct userspace timers */
722 os_alarm_process(get_current()->mm->context.id.u.pid);
723 }
724
725 (*timer_clockevent.event_handler)(&timer_clockevent);
726
727 return IRQ_HANDLED;
728}
729
730static u64 timer_read(struct clocksource *cs)
731{
732 if (time_travel_mode != TT_MODE_OFF) {
733 /*
734 * We make reading the timer cost a bit so that we don't get
735 * stuck in loops that expect time to move more than the
736 * exact requested sleep amount, e.g. python's socket server,
737 * see https://bugs.python.org/issue37026.
738 *
739 * However, don't do that when we're in interrupt or such as
740 * then we might recurse into our own processing, and get to
741 * even more waiting, and that's not good - it messes up the
742 * "what do I do next" and onstack event we use to know when
743 * to return from time_travel_update_time().
744 */
745 if (!irqs_disabled() && !in_interrupt() && !in_softirq() &&
746 !time_travel_ext_waiting)
747 time_travel_update_time_rel(TIMER_MULTIPLIER);
748 return time_travel_time / TIMER_MULTIPLIER;
749 }
750
751 return os_nsecs() / TIMER_MULTIPLIER;
752}
753
754static struct clocksource timer_clocksource = {
755 .name = "timer",
756 .rating = 300,
757 .read = timer_read,
758 .mask = CLOCKSOURCE_MASK(64),
759 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
760};
761
762static void __init um_timer_setup(void)
763{
764 int err;
765
766 err = request_irq(TIMER_IRQ, um_timer, IRQF_TIMER, "hr timer", NULL);
767 if (err != 0)
768 printk(KERN_ERR "register_timer : request_irq failed - "
769 "errno = %d\n", -err);
770
771 err = os_timer_create();
772 if (err != 0) {
773 printk(KERN_ERR "creation of timer failed - errno = %d\n", -err);
774 return;
775 }
776
777 err = clocksource_register_hz(&timer_clocksource, NSEC_PER_SEC/TIMER_MULTIPLIER);
778 if (err) {
779 printk(KERN_ERR "clocksource_register_hz returned %d\n", err);
780 return;
781 }
782 clockevents_register_device(&timer_clockevent);
783}
784
785void read_persistent_clock64(struct timespec64 *ts)
786{
787 long long nsecs;
788
789 time_travel_set_start();
790
791 if (time_travel_mode != TT_MODE_OFF)
792 nsecs = time_travel_start + time_travel_time;
793 else
794 nsecs = os_persistent_clock_emulation();
795
796 set_normalized_timespec64(ts, nsecs / NSEC_PER_SEC,
797 nsecs % NSEC_PER_SEC);
798}
799
800void __init time_init(void)
801{
802 timer_set_signal_handler();
803 late_time_init = um_timer_setup;
804}
805
806#ifdef CONFIG_UML_TIME_TRAVEL_SUPPORT
807unsigned long calibrate_delay_is_known(void)
808{
809 if (time_travel_mode == TT_MODE_INFCPU ||
810 time_travel_mode == TT_MODE_EXTERNAL)
811 return 1;
812 return 0;
813}
814
815int setup_time_travel(char *str)
816{
817 if (strcmp(str, "=inf-cpu") == 0) {
818 time_travel_mode = TT_MODE_INFCPU;
819 timer_clockevent.name = "time-travel-timer-infcpu";
820 timer_clocksource.name = "time-travel-clock";
821 return 1;
822 }
823
824 if (strncmp(str, "=ext:", 5) == 0) {
825 time_travel_mode = TT_MODE_EXTERNAL;
826 timer_clockevent.name = "time-travel-timer-external";
827 timer_clocksource.name = "time-travel-clock-external";
828 return time_travel_connect_external(str + 5);
829 }
830
831 if (!*str) {
832 time_travel_mode = TT_MODE_BASIC;
833 timer_clockevent.name = "time-travel-timer";
834 timer_clocksource.name = "time-travel-clock";
835 return 1;
836 }
837
838 return -EINVAL;
839}
840
841__setup("time-travel", setup_time_travel);
842__uml_help(setup_time_travel,
843"time-travel\n"
844"This option just enables basic time travel mode, in which the clock/timers\n"
845"inside the UML instance skip forward when there's nothing to do, rather than\n"
846"waiting for real time to elapse. However, instance CPU speed is limited by\n"
847"the real CPU speed, so e.g. a 10ms timer will always fire after ~10ms wall\n"
848"clock (but quicker when there's nothing to do).\n"
849"\n"
850"time-travel=inf-cpu\n"
851"This enables time travel mode with infinite processing power, in which there\n"
852"are no wall clock timers, and any CPU processing happens - as seen from the\n"
853"guest - instantly. This can be useful for accurate simulation regardless of\n"
854"debug overhead, physical CPU speed, etc. but is somewhat dangerous as it can\n"
855"easily lead to getting stuck (e.g. if anything in the system busy loops).\n"
856"\n"
857"time-travel=ext:[ID:]/path/to/socket\n"
858"This enables time travel mode similar to =inf-cpu, except the system will\n"
859"use the given socket to coordinate with a central scheduler, in order to\n"
860"have more than one system simultaneously be on simulated time. The virtio\n"
861"driver code in UML knows about this so you can also simulate networks and\n"
862"devices using it, assuming the device has the right capabilities.\n"
863"The optional ID is a 64-bit integer that's sent to the central scheduler.\n");
864
865int setup_time_travel_start(char *str)
866{
867 int err;
868
869 err = kstrtoull(str, 0, &time_travel_start);
870 if (err)
871 return err;
872
873 time_travel_start_set = 1;
874 return 1;
875}
876
877__setup("time-travel-start", setup_time_travel_start);
878__uml_help(setup_time_travel_start,
879"time-travel-start=<seconds>\n"
880"Configure the UML instance's wall clock to start at this value rather than\n"
881"the host's wall clock at the time of UML boot.\n");
882#endif